Ab Initio Study of the Molecular and Electronic Structure of CoCH2+ and of the Reaction Mechanism of CoCH2+ + H2

dc.contributor.author Musaev, Djamaladdin
dc.contributor.author Morokuma, Keiji
dc.contributor.author Gordon, Mark
dc.contributor.author Nguyen, Kiet
dc.contributor.author Gordon, Mark
dc.contributor.author Cundiari, Thomas
dc.contributor.department Chemistry
dc.date 2018-02-17T07:35:08.000
dc.date.accessioned 2020-06-30T01:18:42Z
dc.date.available 2020-06-30T01:18:42Z
dc.date.copyright Fri Jan 01 00:00:00 UTC 1993
dc.date.issued 1993-11-01
dc.description.abstract <p>Both CASSCF and MR-SDCI-CASSCF methods have been used with two different effective core potentials to investigate the molecular and electronic structures of CoCH2+, as well as the mechanism for the reaction CoCH2+ + H2. Four electronic states of CoCH2+ are very low lying: the ground state is a nearly degenerate pair (3A2 and 3A1), and the 3B1 and 3B2 states are only 4-8 kcal/mol higher in energy. The binding energy of C O C H ~ + ( ~ Are~la)t,iv e to that of C ~ + ( ~ F , s l d+~ C)H 2(3B1), is estimated to be 70-80 kcal/mol. A similar hydrogenolysis reaction mechanism holds for the 3A2 and 3A1 states of the CoCH2+ + H2 reactants: In the first step, the reactants yield an ion-molecule complex, (H2)CoCH2+, stabilized by 8-9 kcal/mol. Subsequently, the H-H bond is activated, leading to a four-center transition state with an energy barrier of about 31-34 kcal/mol. An intermediate complex, HCoCH3+, is predicted to be a minimum at the CASSCF level, but MR-SDCI-CASSCF single-point calculations suggest that this minimum disappears at the higher level of theory. Following H-H bond cleavage, a CoCH4+ ion-molecule complex is formed, with a stabilization energy of 19-22 kcal/mol. The CoCH2+ hydrogenolysis reaction is predicted to be exothermic by 20-30 kcal/mol. The channels leading to formation of CoH+ + CH3 and CoCH3+ + H are endothermic by about 5-1 2 kcal/mol. The reverse reaction Co+ + CH4 may give only one product, the ion-molecule complex CoCH4+ at moderate temperatures. An increase in the available kinetic energy would make it possible to form dissociation products: CoH+ + CH3 and CoCH3+ + H. Although the channel leading to CoCH2+ + H2 is thermodynamically more favorable, a large barrier prevents it from taking place. Hay-Wadt and Stevens-Krauss-Basch-Jasien pseudopotentials give qualitatively the same results.</p>
dc.description.comments <p>Reprinted (adapted) with permission from <em>Journal of Physical Chemistry</em> 97 (1993): 11435, doi:<a href="http://dx.doi.org/10.1021/j100146a016" target="_blank">10.1021/j100146a016</a>. Copyright 1993 American Chemical Society.</p>
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dc.identifier archive/lib.dr.iastate.edu/chem_pubs/244/
dc.identifier.articleid 1256
dc.identifier.contextkey 7917355
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath chem_pubs/244
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/14686
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/chem_pubs/244/0-L_1993_Gordon_AbInitioStudy.pdf|||Fri Jan 14 22:53:38 UTC 2022
dc.source.bitstream archive/lib.dr.iastate.edu/chem_pubs/244/1993_Gordon_AbInitioStudy.pdf|||Fri Jan 14 22:53:40 UTC 2022
dc.source.uri 10.1021/j100146a016
dc.subject.disciplines Chemistry
dc.title Ab Initio Study of the Molecular and Electronic Structure of CoCH2+ and of the Reaction Mechanism of CoCH2+ + H2
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 1a5927c0-5a5f-440e-86e0-9da8dc6afda0
relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11
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